Electric switch



NOV. 2, 1937. E;- J, DlLLMAN 2,098,181

ELECTRIC SWITCH Filed March 9, 1934 2 Sheets-Sheet l INVENTO BY f FIG. 5 45 NOV. 2 1937. E. J. DILLMAN 2,098,181

v ELECTRIC SWITCH FWG. 4-

Patented Nov. 2, 1937 UNITED STATES PATENTk OFFICE ELECTRIC SWITCH Application March 9, 1934, Serial No. 714,743

24 Claims.

My invention relates to electrieswitches, and more particularly to a switch which is automatically operable by temperature responsive means or the like.

An object of my invention is to provide an electric switch which is particularly adapted to be secured in heat conducting relation to a fluid conveying conduit or the like so that the automatic means for actuating the" switch will re- 10 spond to the temperature of theiiiuid in the conduit.

Another object is to provide a switch which will have a quick operating action so as to prevent arcing at the switch contacts.

15 Another object is to provide a switch which is readily adjustable to regulate both its range of operation and the differential operation between making and breaking of contact.

Another object is to provide novel means for .,0 adjusting and supporting a magnet cooperable with the contact carrying arm of the switch.

'Ihe invention consists in the improved construction and combination oi' parts, to be more fully described hereinafter and the novelty oi' which will be particularly pointed ont and distinctlyv claimed.

In the accompanying drawings, to be taken as a part of this speification, I have fully and clearly illustrated a switch em odying my invention, in 30 which drawings- Figure 1 is a top plan view of the switch housing, having a top cover or closure member removed to show certain of the internal construction;

Fig. 2 is a view in section on the line 2-2 of Fig. 1, but with the cover member in place;

Fig. 3 is a view in section substantially on the line 3-3 of Fig. 2, and

Fig. 4 is a view of another form oi' switch operating means in longitudinal central section as applied to the switch of Fig. 1.

Referring to the drawings by characters of refercnce. I designates generally a base member, preferably in the form of a rectangular housing having end walls 2, 3 joined by side walls 4, 5 and having a top wall 6 which covers one end portion of the housing, these walls being of electric insulating material. The remainder of the open top of the housing is closed by a cover memer l also of electric insulating material. The bottom wall of the housing is formed by a plate member 8 preferably of metal or other suitable hfat conducting' material which is secured to the housing by screws 9 and which' has end portions I0 projecting beyond the housing end walls for eny resilient sheet metal.

(ci. zoo-13s) gagement by clamping bands/or the like so that the housing and particularly the plate 'member 8 may be secured to a heat conducting surface. Within the housing at one end there is a supporting means preferably in the form of laterally 5 spaced lugs or brackets II which are adjacent to but spaced from the bottom wall 8, Extendinglongitudinally within the housing there is an elongated supporting member I2 preferably of electric insulating material which extends at one end, as at I3, between the lugs II, being pivotally secured thereto by a hinge member I4 of The member I4 has spaced, substantially parallel arm. portions I5 which bridge the space between the lugs II and 15/ lateral flanges I6 adjacent the end portion I3 of the member I2, the arm portions I5 extending parallel to and serving as the fulcrum for the member I2. Each of the arm portions I5 is secured to its respective lug and flange by screws I1, I3 respectively. Between the arm portions I5 20 there is a tongue portion I9 which lies upon the \projecting end I3 and which is turned upward, as `at 2l, and then back upon itself, as at 2|, to provide a supporting bracket arm which normally converges or is inclined toward the portion of member I4 joining the arm portions I5. The bracket arm 2| has an end slot or opening 22 which receives a sleeve member 23 having an end flange engaging the underside of the arm 2 I. The sleeve member 23 extends upward through the 30 slot formed between the arms or poles 24 of a U-shaped permanent magnet 25 and through an aperture in a dial plate 26 which rests upon the top face of the magnet. The plate 26 and magnet 25 are secured to the arm 2| by a nut 21 which is screw-threaded on the upper end portion oi the sleeve member 23. The bore of the sleeve member 23 is screw-threaded to receive an adjustment screw 23 which bears at its lower end on the hinge 40 member I4 between the arm portions I5. The upper end of the screw 28 is provided with a laterally projecting arm 29 by which the screw may be-rotated and serves as a pointer cooperable with suitable indicia 30 carried by the dial plate 25. 45 The arm 29 cooperates with stop members 3| which project upward from the plate 26 to limit rotation oi' the screw 23. The plate 26 is provided with a lip or flange 32 which engages the base of the magnet to prevent movement of the stop members 3i when they are engaged by the arm 29. Pivotally secured to the supporting member at its end opposite the magnet 25, there is a contact carrying arm 33. The pivotal connection for the arm 33- is formed by a hinge member 34 such as a plate of resilient sheet metal rivet/ed or otherd wise secured, as at 35, to one end oi arm and secured by screws 33 or the like to the end of the supporting member l2. The end of the supporting member i3 to which the arm is secured is provided with a step or transverse extension 3l to the top face oi which the hinge member is secured by the screws 35 so that the arm 33 is in spaced overlying, substantially parallel relation to the supporting member l2. The arm extends longitudinally of the member i3 toward the magnet 25 and terminates in an armature portion 33 which overlies and cooperates with the magnet poles 23. The arm 33 carries a. contact member 33 which is xed to the free end of a leaf spring di! extending longitudinally of the arm 33 and secured thereto, as at lill, by a rivet and clamping plates. The. contact member 33 is provided with a neck portion received by a slot in the arm 33 so that the contact member is movable transversely to the arm 33. The contact member 33 extends toward the supporting member |13 and cooperates with a contact member 32 rigidly secured to and projecting from the member i3 between the magnet poles 22d. The contact member l2 is preferably in the iorm of a post which: is screw-threaded, as at d3', in the bore of an insert embedded in the top face of the member l2. A flexible lead wire i3 has one end secured to the contact member d3 by a flange on the contact member which clamps the end of the lead wire against the supporting member l2. The

' other end of the lead wire 33 extends through an aperture in the front housing wall d 'into an outlet box dit formed integral with the housing mem,

ber. This other end of the lead wire 33 is secured to a terminal member 35 having a binding screw l5 positioned in thel outlet box d3. A stop member il of inverted lll-shaped form bridges the arm 33 and has its ends secured, as at 33, in the supporting member l2 adjacent the armature 33 to limit movement of the arm away from the supporting member i3. The cover member l has an extension 35 see Fig. 4, which overlies and closes the open top oi the outlet box dit. Transversely through the ytop wall t there is an opening in which is secured an internally screwthreaded sleeve member 53 which projects from the top face of the wall t. Threaded in the bore of the sleeve member 53 there is an adjustment screw 5l having a knob 52 ilxed on its outer projecting end. The knob 53 is provided with a iinger 53 cooperable with a dial 53 on the top face of wall 6 ton'ndicate its position of adjust ment and also cooperable with' a stop member 55 projecting from the wall t and preferably integral therewith to limit rotation of the adjustment screw 5i. The inner end of the screw 5l is provided with a socket or recess 56 to receive Y one end of a pin or rod 5l which extends through an aperture 53 in the arm 33 and into a socket or recess 53 in the top face of the supporting member i2. Between the recess 53 and the pivotal support for the arm 33 there is a guideway t3 extending transversely through the supporting member i2 and having its longitudinal axis transverse to the arm 33. In the guideway 60 there is a longitudinally reciprocable operating or thrust member 5t which projects at its ends from the opposite faces of the supporting member l2.

`rThe thrust member 6l is preferably in the form of a cylindrical' rod having conical or pointed end portions of-Which one end portion engages the underside of the arm 33 adjacent its fulcrum so as to swing the arm 33 away from the encarar supporting member lli. The other pointed end of the thrust member 5l abuts the free end portion 53 of a thermostatic blade or element 53 of bimetal which serves as a power means for moving the thrust member 5i and actuating the arm 33. The blade 53 extends longitudinally of the supporting member i3 and substantially parallel thereto, being rigidly xed to the bottom housing wall 3 in heat conducting relation thereto by rivets tl or the like adjacent the end housing wall 2. The contact member 33 is supplied with current by a exible lead wire 55 having one end secured to the hinge member 3d by one of the screws 35.

The other end of the lead Wire t5 extends through bend. or warp at its free end portion 32 away from the plate 3. Movement of the end portion 52 will move the thrust member toward and into engagement with the contact carrying arrn.3 3 and when the force exerted by the thermostatic element 53- exceeds the attractive force of the magnet for the armature portion 33, the contact members 39 and 32 will be separated with a quick, substantially snap action. Due to the lost motion-between'the arm 33 and the contact supporting leaf spring d3, the arm 33 will be in motion prior to engagement of the arm 33 with the spring til which results in movement of Contact member 33. When the thermostatic element t3 cools after contact has been broken such that its free end portion 62 moves toward the plate 3, the thrust member 3l will move therewith under the force of the resilient hinge member 3ft which acts against the thrust member tl through the arm 33 and causes the arm 33 to approach the magnet 25. When the armature portion 33 has moved suc'ientl'y into the yfield ofthe magnet 35, the attractive force of the magnet acting on the armature portion 38 will pull the arm 33 quickly toward the supporting member i2 and the contact member 39 into engagement with the fixed Contact member 32. Movement of the arm 33 toward the magnet will be limited by engagement of the arm with the head of the contact member 33, the arm having slight movement against the resilient force of leaf spring Ml after contact is made. The range of operation of the instrument may be controlled by adjustment of the knob 52. Adjustment of the knob to move the supporting member l2 against the resilient force of its supporting hinge member M toward the plate 3 will result in the thermostatic element 33 acting to breakcircuit between the contact members 39 and ,42 at a lower temperature. When the knob 52 is rotated counterclockwise of Fig. 1, the resilient hinge member i4 will move the supporting member l2 away from the plate 3 and maintain the supporting member in engagement with the` rod 5l. Movement of the free end of the supporting member l2 away from the plate 3 will require a higher degree of temperature to break circuit as the thermostatic element must have greater movement in order to actuate the arm 33 to break contact between the contact members 39 and 42. strument is controlled byv the magnet 25. If the adjustment screw 28 is turned in a clockwise The diierential operation of the inf co direction facing Fig. 1 so that the magnet poles 24 are moved away from the supporting member I2 and toward the armature portion 38, the differential between making and breaking of contact will be increased as the thermostatic element 63 will have to exert a greater force to overcome the attractive force of the magnet. The magnet is held in its adjusted position by the inherent resilience of the supporting bracket which urges the magnet poles toward the supporting member l2. When the adjustment screw 28 is rotated in a counterclockwise direction facing Fig. 1 to permit movement of the magnet poles toward the supporting member I2 by the inherent force of the magnet supporting bracket, the air gap between the magnet poles and the armature portion 38 will be increased thereby decreasing the diierential operation of the instrument. Since the magnet 25 and the contact members 39, 42 are carried by the supporting member I2, the differential operation of the instrument will not be affected by the adjustment of the operating range. 1

In Figure 4, the housing for the switch mechanism which is substantially identical with that above described and therefore not shown is separated from the thermostatic switch operating element so as to prevent transmission of heat to the switch mechanism from the heat source to which the thermostatic element is subjected. 'I'he housing member I is provided in lieu of the plate 8 with a closure plate 68 which is apertured coaxially with the thrust member 6| to receive a sleeve member 69 having a tubular'casing 10 reciprpcably guided in its bore. Fixed in the inner end of the casing 10 there is a plug member 1| which engages the thrust member 46|. Reciprocable in the casing 10 and positioned at the other end thereof there is an abutmenty member 12 through which a rod 13 extends, the rod being rigidly xed to the abutment member. The end portion of the rod 13 withinvthe casing 10 is guided for reciprocation in a longitudinal guideway 14 in the plug member 1|. A helical coil spring 15 surrounds the rod 13 within the casing 18 and seats at its opposite ends against the plug member 1| and the abutment member 12 so that the rod 13 normally acts to move the casing 10 but is permitted lost motion relative theretoupon compression of the spring 15. The end of the casing 10 is provided with an inturned flange 16 which prevents movement of the abutment member 12 out of the casing. The rod 13 extends at its'other end into a casing l1 through a guideway 18 in a supporting member 19 secured in an aperture 80 through a wall of the casing 11. lThe wall of the casing 11 opposite the supporting member 19 is formed by a metal plate member 8| which is secured inposi-A tion by screws 82. The plate member 8| has projecting end portions 83 which extend beyond the end Walls of the casing and which are adapted to be secured by clamping bands or the like to a conduit or` other heated or cooled surface. A thermostatic element 84 is positioned within the casing 11 and is xed at one end by rivets 84' or the like to the inside face of the plate 8|. The element 84 extends longitudinally of the casing and at its free end portion 85 is in abutting relation to the end of the rod 13 which extends into the casing 11. The element 84 extends transversely to the rod 13 so that when it bends or warps in response to temperature change to which the plate 8| is subjected, it will push on the end of the rod 13. 'I'he rod 13 extends longitudinally through a tubular supporting member 86 which extends at its opposite ends into cylindrical bores or sockets 81, 88 formed respectively in the sleeve member 69 and the supporting member 19. The tubular member 88 is secured in its respective end sockets by set screws 89, 90 so that the casing 11 and the housing member are rigidly connected together with the housing member supported from the casing T1. The tubular member 86is provided with heat radiating ns 9| which are apertured to receive the tubular member 86 and which provide an extended cooling surface to prevent transmission of heat from the casing 11 to the housing member l.

The operation of the device of Figure 4 is as follows: When the temperature to which the element 84 is subjected by conduction fthrough the casing wall 8| increases, the free end portion 85 thereof will bear against the end of the rod 13 and move it together with the tubular casing 13 toward the housing member The casing 10 will move with the rod 13 due to the interposed spring 15. The movement of the casing 10 will be transmitted through its plug member 1| to the thrust member 6| which engages the contact carryingarm 33. When the forc'e exerted by the ,element 84 becomes suilcient to overcome the magnet acting on the arm 33, contact will be broken as above described in connection with Figures l, 2, and 3. Should the element 84 continue to push on the rod 13 after the arm 33 has reached its limit of movement as determined by the stop memberA 41, then the spring 15 will permit overtravel of the rod 13 without movement of the casing 10 and the thrust member 6|. When the element 84 cools in response to lowering of tem-- perature to which it is subjected, the hinge member 34 will move the thrust member 6| and rod 13, maintaining the thrust member in engagement with the rod 13 and the rod in engagement, with the element 84 until the contact carrying arm 33 has reached its limit of movement toward the supporting member |2 and contact is made.

Although the thermostatic elements 63 and 84 have beendescribed as acting to break circuit on rise of temperature, it will be obvious that their operation may be reversed so that they move away from their supporting plates and break circuit on decrease of temperature to which they are subjected. l f `What I claim and desire to secure by LettersX Patent of the United States is: l. A device of the character described, comprising a base member, a supporting member adjustably mounted at one end on said base member, a permanent magnet adjustably supported on said supporting member and extending longitudinally thereof, means to move said magnet relative to said supporting member, a contact member on 6 said supporting member adjacent the inner end of said magnet, a contact carrying arm pivotally secured at one end to said and extending longitudinally thereof into spaced overlying relation to said magnet and said contact member, a contact member carried by vsaid arm and cooperable with said first-named contact member, power means for actuating said arm and operatively connected thereto, and means to adjust said supporting member relative to said base member whereby to regulate the operation of said arm by said power means.

2. A device of the character described, comprising a base member, a supporting Vmember ad- `iustably mounted at one endon said base member,

supporting member member, a thrust member reciprocably supported 4by said supporting member andengaging said arm, and power means engaging said thrust member to actuate said arm.

3. A device -of the characterdescribed, comprising a base member, a supporting member adjustably mounted on said base member and having a laterally extending portion, a contact member fixed to said supporting member,l a contact carrying arm extending substantially parallel with said supporting member and having a contact member cooperable with said first-named contact member, resilient hinge means connecting said arm at one end to theextended portion of said supporting member and acting through said arm to hold said second-named contact member in engagement with said rst-named contact member, a bimetal element for actuating said arm, means operatively connecting said element and said arm for transmitting movement of said elementy to said arm to part said contact members, and -means to adjust said supporting member relative to said base member whereby to regulate the operation of said arm by said ele- O ment.

4i. A device of the character described, comprising a supporting member, a resilient support- 'ing arm in spaced overlying relation to said member and secured thereto, a magnet mounted on said arm, means securing said maghetto said arm, means for adjusting said magnet relative to said supporting member, said adjusting means being carried by said securing means, a contact carrying arm cooperable with saidmagnet, and means to actuate said contact arm.

5. A'device of the character described, comprising a supporting member, a resilient supporting arm in spaced overlying relation to said ymember and secured thereto, a magnet mounted on said arm, means securing said magnet to said arm, means for adjusting said magnet relative to said supporting member, said adjusting means being carried by said securing means,v a stop member cooperable with said adjusting means and Afixed to said magnet by said securing means. a

contact carrying arm cooperable with said magnet, and means to actuate said contact arm.

6. .A device of the character described, comprising a supporting member, a resilient supporting arm in spaced overlying relation to said member and secured thereto, a' magnet mounted on said arm, means securing said magnet to said arm, means for adjusting said magnet relative to said supporting member, said adjusting means being carried bysaid securing means, a contact carrying arm cooperable with said magnet,

a resilient hinge member securing one endof-sad contact arm to said supporting member, and operating means acting on said contact arm adjacent said hinge member.k

'7L A device of the character` described, comprising a base member, a supporting member, a resilient hinge member rigid with said base member and secured to one end of said supporting member, an adjustment member engaging said supporting member, a magnet adjustably mounted on said supporting member and extending longitudinally thereof, a contact carrying arm overlying said supporting member and cooperable with said magnet, a resilient hinge member rigid with said base member and secured to one end of said contact arm, a thrust member reciprccably guided in said supporting member and engageable with said contact arm, and temperature responsive means for moving said thrust member.

8. A device of the character described, comprising a base member, a. supporting member, a resilient hinge member rigid with said base' member and secured to one end of said supporting member, an adjustment member engaging said supporting member, a magnet adiustably mounted on said supporting member and extending longitudinally thereof, aicontact carrying arm overlying said supporting member and cooperable with said magnet, a resilient hinge member rigid With said base member and secured to one end of said contact arm, a. thrust member' reciprocably guided in said supporting member and engageable with said contact arm, and a bimetal blade having one end rigid with said base member and having its other end engaging said thrust member.

9. A. device of the character described, comprising a housing member, .a supporting member pivotally secured at one end to an end Wall of said housing member, a magnet adjustably supported on said one end of' said supporting member, a contact carrying arm pivotally supported at the other end of said supporting member and extending into overlying cooperable relation to said magnet, said contact arm 'having an opening therethrough, an adjustment member extending through said opening into engagement with said prising a housing member, a supporting member pivotally secured at one end to an endvvall of vsaid housing member, a magnet adjustably sup'- ported on said one end of said supporting membei', a contact carrying arm pivotally supported at the other end of said supporting member and extending into overlying cooperable relation to said magnet, said Contact arm having an opening therethroughan adjustment member extending through said opening into engagement with said supportingv member, means carried by the top vWall of said housing member for actuating said adjustment member, Da bimetal blade having one end xedand having its other end movable for actuating said contact arm, and an operating member interconnecting said other blade end and said contact arm, said operating member including lost-'motion means to permit overtravel ci said blade.

11. A device of the character described, comprising a housing' member, a supporting member' pivotally secured at one end to anend Wall of said housing member, a magnet adiustably supported on said one end of said supporting member, a contact carrying Varm pivotally supported at the other end of said supporting member and extending into overying cooperable relation to said magnet, said contact arm having an opening arm in spaced ing therethrough, an adjustment member extending through said opening into engagement with said supporting member, means carried by the top wall of said housing member for actuating said adjustment member, a bimetal blade, a plate member supporting said blade, a. tubular member supporting said plate member and secured to said housing member, an operating member reciprocably guided in said tubular member and operatively connecting said blade and said Contact arm, and cooling fins on said tubular member.

12; A device of the character described, comprising a supporting member, a U-shaped supporting means of resilient sheet material secured to said member, a magnet mounted on said means in spaced relation to said member, an adjusting Screw, me-ans rigid with said magnet and carrying said screw, said screw, acting aga-inst said supporting member upon adjustment of said magnet, a control arm cooperable with said magnet, and means to actuate said arm.

13. A device of the character described, comprising a supporting member, a resilient supporting arm in spaced overlying relation t'o said member and secured thereto, a magnet mounted on said arm, means securing said magnet to said arm, means for adjusting saidlmagnet relative to said supporting member, said adjusting means being carried by said securing means, a control arm cooperable with said magnet, means to actuate said control arm, and means to limit operation of said adjusting means.

14. A device of the character described, comprising a supporting member, a resilient supportoverlying relation to said member and'secured thereto, a magnet mounted on said arm, means securing said magnet to said arm, means for adjusting said magnet relative to said supporting member, said adjusting means being carried by said securing means, a control arm cooperable with said magnet, means to actuate said control arm, and cooperable means carried by said adjusting means and by said magnet and operable to limit adjustment of said adjusting means.

15. A device of the character described, comprising a supporting member, a supporting arm in spaced overlying relation to said member and movably secured thereto, a magnet mounted on' and xed to said arm, an adjusting screw carried by said magnet and cooperable ,with said supporting member for relative thereto, a control arm cooperable with said magnet, and means for actuating said control arm.

16. A device of the character described, comprising a supporting member, a supporting arm in spaced overlying relation to said member and movably secured thereto, a magnet mounted on and xed to said arm, an adjusting screw carried by said magnet and cooperable with said supterial closing one side of said casing, temperature responsive means secured to said plate member within said casing wherebylto respond to the 'temperature of said plate member, control adjusting said magnet mechanism within said casing, an adjusting member cooperable with said mechanism to control the range of operation thereof and extending out of said casing, means in said casing to regulate the diil'erential operation of said mechanism, and a removable cover member on said casing whereby said last-named means is accessible.

18. A device of the character described, comprising a casing, a supporting member fulcrumed at one end in and to said casing, a switch arm carried by said supporting member and having an aperture therethrough, a contact member mounted on said supporting member and cooperable with said switch arm, means to actuate said switch arm, said casing having an opening through a wall thereof in registry with said aperture, an adjustment member extending through said opening and said aperture and engaging said supporting member, a hand grip member having an indicator and xed to said adjustment member external of said casing, and a dial on said casing cooperable with said indicator.

19. A device of the character described comprising a base member, a supporting member movably carried by said base member and having an aperture therethrough, a switch arm movably carried by said supporting member on one side thereof and overlying said aperture, means cooperable with said switch arm to control an electric circuit, a temperature responsive element for actuating said switch arm and disposed on the other side of said supporting member in overlying relation to said aperture, a thrust member positioned in said aperture for sliding movement relative to said supporting member andV member and operable to move the ysame whereby to regulate the operation of said mechanism, means to adjust said switch mechanism to regulate the differential operation thereof, a guide bore through said supporting member, anda thrust member reciprocable in and projecting at its opposite ends from said bore, said thrust member having operative engagement with said switch mechanism and with said actuating means.

21. A control device comprising a housing having an opening in a wall thereof, a removable closure member of heat conducting material closing said opening, an adjustable supporting member carried by and disposed within said housing, a contact member mounted on said supporting member, a magnet mounted on one end of said supporting member and having a pole extending toward said contact member, a contact.` carrying-arm movably mounted on the opposite end of said supporting member and having an armature portion extending into cooperable relation to said magnet, a contact member mounted on said arm and cooperable with said firstnamed contact member, an operating member carried by and on the inner wall of said removable closure member and removable therewith as a unitary structure, said operating member being mechanism, an -adjustment member engaging said supporting operable to actuate said arm, and means to adjust 'l5 said supporting member relative to said operating member. I

22. A control device comprising a housing hata ing an opening in a wall thereof, a remcvabie closure member of heat conducting material clou ing said opening, an adjustable supporting mein ber carried by and disposed within said housing with oneside of said supporting member disposed toward said closure member, said supporting member having an aperture therethrough, a contact member carried by said supporting meniber, a magnet carried by and disposed adjacent one end of said supporting member and having a pole extending toward said contact member, a resilient Contact carrying arm movably mounted on the opposite end of said supporting member, said arm being mounted on the opposite side from said one side of said supporting member in overlying relation to said aperture and having anI armature portion extending into cooperabie relation with said magnet, a contact member carried by said arm and cooperable with said first-named contact member, a temperature reg. sponsive blade carried by and on the inner Wall of said closure member, said blade having a free end positioned in overlying relation to said ancr ture on said one side of said supporting member, a loosely disposed connecting member dised for reciprocal movement in said aperture for operatively connecting said blade and said arm, and means to adjust said supporting member relative to said blade to regulate the operation of said larm by said blade.

23. A device of the character Ydescribnli vcom prisingt a base member, a supporting member movabiy carried by said base memr, a switch blade mpvably carried by said supporting mem ber and having an aperture overlying said supporting member, means cooperable with said -ing an Yaperture therethrough, a switch blade movably carried by saidsupporting member and overlying said aperture, said blade having an aperture therethrough, means cooperable with said blade to control an electric circuit, a tempcrature responsive element for actuating said blade. manually operable means for movingl said supporting member to regulate the operation oi said blade by said element and having a socket, and a pair of laterally positioned thrust mem.- bers, one/of said thrust members engaging .in

said socket and extending through said aperture in said blade to engage said supporting member, the other of said thrust members extending through the aperture in said supporting memf ber .and operatively connecting said blade and said element. r 

